I would not knock out SIR2 genes as these:"Sirtuins are hypothesized to play a key role in an organism's response to stresses (such as heat or starvation) and to be responsible for the lifespan-extending effects of calorie restriction".(Check out the new wonder herb resveratrol claiming to activate SIR2)

IGF-1 is probably what you meant, and it is connected to DAF2, which has been shown to be also in Humans and well conserved from the C. elegans. This also regulates aging and stresses, and I would not want to eliminate these two genes. Even though the two genes were mutated in an experiment with worms and the worms lived longer lives, remember that they were mutated in a way that was conducive to living a longer life, but not knocked out entirely.

I think that in this day and age, we should knock out the stressor genes: cortisol, perhaps epinephrine (or any other gene that regulates the fight or flight response), and the ones that make us worry constantly - (neurobiological ones). Free radical scavengers are still the best bet to have to live longer, and boost up the cytochromes in the liver to detox ourselves of all the xenobiotics we put into our bodies.